What are the differences between iPhones 4, 4S, and 5?

We had no money this December, and so we're gonna have a late Christmas in mid-January.
The question is pretty self-explanatory. Don't tell me Apple sucks or whatever, I want an iPhone and I'm wondering if the 4S/5 are worth the extra money or if I should just get 4.

Get 4s excelent device i have ever used

Each phone is depending on what you want out of your phone and what you're willing to pay for it.

Your question says nothing about those things or even what you are being asked to pay.

Don't get the iPhone 4!
The iPhone 4 is horrible now. The A4 chip is a singe-core chip that can't handle iOS 7 well. The A4 chip is really slow. Get an iPhone 4S. It got the same 8 Megapixel camera as iPhone 5. The A5 dual-core chip in iPhone 4S is fast and can handle iOS 7. The iPhone 5 got a better front-camera than iPhone 4S but that doesn't matter for me. The iPhone 5 got a 32-bit system chip named ''A6'' and Apple said that it's twice as fast than iPhone 4S and i agree. Go for 4S.
I'm going to upgrade from iPhone 4 to iPhone 4s.
I did my best.